The invention relates to a process of feeding ruminant animals and to a composition for use therein. More specifically, the invention relates to a process and composition which allows ruminant animals to be fed increased amounts of fat in their diet without deleterious effects on the microorganism populations within the ruminants' stomachs.
Conventional cattle feeds, such as corn and alfalfa, often fail to provide sufficient energy for cattle, especially lactating dairy cattle during periods of heavy milk production. Feed containing a high proportion of corn also has a tendency to depress the milk fat content of the milk produced by such cattle. Fat (a term which is used herein to include both fats which are solid and oils which are liquid at ambient temperature, and includes material from both animal and vegetable sources) is an excellent energy source, and it has been suggested that if the proportion of fat in cattle food could be increased, lactating dairy cattle could produce high milk yields without draining their reserves of body fat and without diminishing the proportion of milk fat in the milk produced.
Large quantities of fat are available commercially as a by-product of the meat packing, fast food and other industries, and this waste fat has already been successfully used in poultry rations. However, although poultry can metabolize fat without any undesirable side effects, it has been found that if the proportion of fat in the diet of cattle exceeds about 2% of the total feed solids, the feed has toxic effects upon the microorganisms in the rumen of the cattle. It appears that fat reduces the growth rate or even kills certain microorganisms which digest fiber in the cow's rumen, thereby lowering fiber digestibility. This deleterious effect on the cow's rumen is particularly true of unsaturated fats. Although the decreased fiber digestion in the rumen is partially compensated by greater fiber digestion in the lower parts of the alimentary canal, such later fiber digestion produces a blend of different fatty acids than that which is produced by the digestion in the rumen and the different blend of fatty acids is less suited to the cow's metabolism.
It has previously been proposed to feed fatty acids to cattle in an encapsulated form in order to avoid the aforementioned effects on the cattle's rumens. Encapsulation techniques previously proposed include coating the fat particles with a protein which is then cross-linked with formaldehyde. However, formaldehyde has many undesirable physiological effects and the potential health threat to both cattle and humans from including formaldehyde in cattle feed prevents such formaldehyde-protein encapsulated fat being used in commercial dairy herds.
There is thus a need for a process whereby fats, or at least the essential dietary constituents thereof, i.e. fatty acids, can safely be fed to ruminant animals without interfering with the animals' rumens' microorganism population. The instant invention provides such a method.